PRECISE: Targeted ablation eliminated symptomatic AF

DENVER — In patients with paroxysmal atrial fibrillation, ablation that targets the elimination of stable rotors and focal sources may be successful for the improvement of asymptomatic atrial fibrillation without the need for pulmonary vein isolation, according to results of the PRECISE trial presented here.

Researchers for the PRECISE trial recruited 31 consecutive patients (mean age, 59 years) with paroxysmal AF who had no previous ablation. On average, AF duration was 4 years, CHADS score was 1.5, left atrium size was 44 mm and 75% had hypertension.

Researchers used a novel mapping system (RhythmView, Topera, Inc.) to target focal impulse- and rotor-guided ablation without pulmonary vein isolation at five study sites. Focal impulse and rotor mapping (FIRM) revealed a mean number of 2.5 AF-sustaining rotors per patient (two-thirds in the left atrium; one-third in the right atrium). Pulmonary vein isolation to eliminate possible triggers was not performed, per protocol.

“Interestingly, many of the sites were in the right atrium. Pulmonary vein isolation is focused on the left atrium. These were sites that we wouldn’t normally target,” Sanjiv Narayan, MD, PhD, professor of medicine and director of electrophysiology at University of California San Diego School of Medicine/VA Medical Center, said at a press conference.

The primary endpoint was elimination of rotors and sources. On follow-up, the success rate of FIRM-guided ablation was 83% after a single procedure.

Average time for this AF ablation was 17.4 minutes of radiofrequency (one-third in the right atrium), Narayan said at a late-breaking clinical trials session.

Complications observed included dislodgement of a right atrium pacing lead which was repositioned with no subsequent complications.

Narayan also presented single-procedure long-term efficacy outcome data from PRECISE. During a mean 223 days of follow-up, freedom from AF after a single procedure was 82.6%, with 64.5% of patients having implanted devices for monitoring. This compares favorably with results from recent trials such as STOP-AF and MANTRA-PAF, which included more than one procedure, he said.

Narayan concluded: “Paroxysmal AF is a substrate-based disease that can be eliminated by FIRM activation of its primary sustaining mechanism — stable rotors and focal sources — without pulmonary vein isolation.”

Addition study is required in patients with persistent AF, he said. – by Deb Dellapena

For more information:

Narayan S. LB01-05. Presented at: Heart Rhythm Society’s Annual Scientific Sessions; May 8-11, 2013; Denver.

Disclosure: Narayan reports that he is coauthor on intellectual property owned by the University of California and licensed to Topera. He reports equity interest in and is a consultant to Topera.